Lock mechanisms, such as the park lock of a vehicle, are often manually operated. However, this means that they may be subject to abusive treatment by an operator. For example, if engagement is attempted at high vehicle speeds, the loads through the lock components and their mountings can be excessive. Also, manually-operated locks tend to require detailed dynamic analysis, testing and development to ensure that the components are sufficiently durable.
Electrically-operated park locks can significantly reduce the requirement for detailed analysis and testing of their components, as their abusive operation can be prevented by their electrical control system. They must though be configured in such a way that the park lock is engaged and the associated shaft locked when power to the vehicle is disconnected. In the case of a system actuated by a solenoid, it must therefore be configured so that the lock is engaged when the solenoid is de-energised. This means that electrical power is required at all times during normal vehicle operation in order to keep the park lock disengaged. Constant operation of the electrical system of the lock is a constant drain on the vehicle power source and can also compromise the durability of the brake owing to the associated heat generation.
An electrically-operated system may also be powered by a motor. This may avoid the need for constant power for the lock to remain disengaged during vehicle use. However, the size of the motor may cause packaging issues and additional cost may be involved in adapting a motor to the vehicle's mechanical system.